1. Field of the Invention
The present invention relates to an initialization method for a network system and, more particularly, to an initialization method adaptive for a Gigabit Ethernet system.
2. Description of Related Art
For an Ethernet system, a receiver to accurately receive data at a receiving-end may include the following devices: a feed-forward equalizer (FFE), a feed-back equalizer (FBE), a timing recovery (TR), an ECHO canceller, an NEXT (Near-End-Cross-Talk) canceller, etc. In order to find the appropriate coefficients of the devices, the conventional method, which is known to be a data-directed approach, is that the transceiver of the transmitting-end transmits signals known by both ends to the transceiver of the receiving-end and the appropriate coefficients for the devices of the receiving-end are determined according to the receiving known signals.
However, according to the IEEE 802.3ab standard, a decision-directed approach is introduced to determine and/or adjust the appropriate operating coefficients of the devices. When determining the appropriate operating coefficients of the devices, the receiving signals are unknown by the receiving-end in advance. However, since the operation of the devices may have interaction to each other when determining the coefficients, the determined coefficients of the devices may not be converged to an appropriate value. Thus, signals transmitted by the transceiver cannot be received.
To solve the aforementioned problem, the functions of some function blocks are simplified or the coefficients of some function blocks are fixed. In this manner, the interaction between functional blocks is reduced and the time for convergence of each functional block is reduced. However, the determined coefficients may not be optimized. In U.S. Pat. No. 6,201,831, Inter-Symbol-Interference (ISI) is divided into a precursor and a postcursor caused by a pulse-shaping filter on the transmitting-end and the channel response respectively. Accordingly, an inverse partial response filter (IPR) and a decision feedback sequence estimator (DFSE) on the receiving-end are used to eliminate the precursor and the postcursor respectively in turn. However, in practice, the ISI, especially the precursor, still exists when the conventional art is applied. Thus, the performance of the initialization of the Gigabit Ethernet system needs to be further improved.
Therefore, it is desirable to provide an improved initialization method for a Gigabit Ethernet system to mitigate and/or obviate the aforementioned problems.